Three-dimensional (3D) video images for consumer television and other applications have become widespread. The hardware for 3D video images is well-known and typically involves substantially identical left and right video image channels of the same scene, except that the two image channels are taken from different lateral positions often separated by a few inches, yielding slightly different images so as to mimic views from each of a person's eyes. Viewers usually look at the 3D display via special glasses or Fresnel lenses, which allow each video image channel to effectively reach one eye only, which projects two slightly different images onto the retinas of the viewer's eyes. The viewer's visual cortex processes the binocular disparities of the two slightly different images together in a way that permits 3D, or stereoscopic depth perception.
A 3D display utilizing technologies described above typically requires a viewer to view the images being displayed from within a volume of space in front of the display for optimal 3D viewing. If the viewer's head leaves this volume of space in front of the display, the stereo image visualized by the viewer may be adversely affected, which may create eye strain and may lead to improper viewing of the 3D images, and therefore should be avoided.